In recent years, mobile phones with a GPS (Global Positioning System) function have appeared, which communicate with a server to obtain service provided by the server to find a route from a point of departure to a destination. In use of such service, users visually check map information displayed on a display mounted on a mobile phone while moving from a point of departure to a point of destination and can reach the destination with assistance of voice guidance, if necessary.
On the other hand, a map includes essential facilities such as convenience stores and gas stations, in addition to route information. Users often wish to drop in at desired facilities on the way to the destination using the navigation function of mobile phones. A technique of displaying a facility included in a map is disclosed in Japanese Patent Laying-Open No. 2002-328031 (Patent Document 1), though not being directed to a mobile phone. A navigation apparatus disclosed in Japanese Patent Laying-Open No. 2002-328031 includes a facility information storage means for storing facility information including the address or the type of a neighboring facility, a search condition input means for inputting a predetermined search condition through a user's operation, a search means for searching for said neighboring facility that satisfies said search condition input by said search condition input means, based on said facility information stored in said facility information storage means, a search result graphic means for generating search result graphic data in which, for said neighboring facility within a predetermined range that is extracted through a search by said search means, a type mark corresponding to said type is arranged corresponding to an approximate location of the address, and a display means for displaying a search result based on the search result graphic data generated by said search result graphic means.
However, the user has to watch the map displayed on the display mounted on the mobile phone and visually check the location of the facility while moving. A display on a mobile phone has a problem in that it is difficult to recognize the displayed map and the locations of essential facilities on the course of the route, because the display area is smaller than that of a display mounted on a car navigation apparatus and because the resolution or contrast of the display is limited. Therefore, the user may move ahead to a wrong direction or may miss the essential facilities without being aware of their existence even if they are located in the user's proximity. In particular, during the night when the environment is dark, it is difficult to check the map displayed on the display, because the backlight which illuminates the display turns off after a lapse of a prescribed time in order to reduce battery consumption.